Case

Location: Dhaka, Bangladesh

Wells in Dhaka usually had a lifespan of about one year before the amount of drinking water would drop. The reason for this is that a well can only give a certain amount of water. If you try to suck more water out of this well, the wall of the well will get clogged, and less and less water will be entering the borehole.

To show how another design of a borehole can provide a certain amount of water for more than twenty years, the Bangladeshi and Dutch drinking water company decided to make a new well.

Assignment

During this project we were responsible for the selection of both the new borehole pump and the frequency inverter that accompanied it. We would also supervise and coordinate the proper assembly and installation of the borehole pump.

Drilling a new well – © Oveducon

Execution

First we supervised the new installation of the electrical cabinet. They were used to just have a few wires mounted to the wall, but this could cause problems regarding safety and cooling in the future. Therefore, in close collaboration with the Bangladeshi drinking water company, we decided to make a new panel according to European standards, to feature as an example for future projects.

While we coordinated the installation of the new borehole pump, we encountered some obstacles. For instance, when the pump was delivered we noticed that it did not meet the set requirements on the quota. The cable that was included was not the specified length. Therefor we were forced at the last minute to find a new cable in Dhaka if we wanted to stay on schedule. Luckily we found a suitable cable and around midnight we were able to make a watertight cable connection.

Once assembled, we carefully lowered the pump into the borehole and made sure that a safety cord got attached to the pump to prevent it from falling to the bottom of the well. During the last stages of the installation of the borehole pump we had to intervene and interrupt the work.

After we finished the installation of the pump, we made sure that the frequencyinverter was properly configured and created a list of all the proper settings for easy future reference.

Results

After some lab tests of the water quality, the pump could be put to use and is now running for more than 8 years straight without any problems or drop in capacity. In a city where the average lifespan of a deep well is 12 months, this is very special.

The pump and borehole designers are now working according to the new design and therefore it is possible to produce more drinking water with the same amount of pumps. This is because there are increasingly less pumps that malfunction. Because of this, they saved more than 50 pumps in five years.

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